Why am I getting a message that says Buy with your team when logging into Guided Buying?

The 2105 release included the new feature Team Buying. Every user will see this pop up the first time they log in to GB.

If the feature is not configured in your realm, end-users will still see the pop-up message the first time, even though they wont be able to use it.

Guided Buying > Guided Buying Approval/Notifications